Windows, doors and glazing
The sealed unit in a roof window is misted and the flashing was not seen from outside. What of the glass has failed, and what of the flashing is unverified?
The sealed unit has failed, and the flashing is unverified because it was not seen from outside. Mist between the panes is the glass itself: the seal has gone and moisture is in the cavity of the unit. That is a glazing failure. The flashing that weathers the window into the roof was not seen from outside, so the survey has not called it sound and has not called it split. Two parts, and only the glass has been judged.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
A misted unit can be renewed without the flashing being the cause, and a poor flashing can wet the ceiling while the glass stays clear. Here the glass has already failed, and the flashing was simply not in view. The survey did not climb to it and did not strip it. Internal mist is enough to call the unit failed. It is not enough to call the flashing failed or intact. The covering around the window stays a separate question.
Ask a roof-window firm to replace the failed unit and to inspect the flashing from outside at the same visit. Tell the solicitor the glass has failed and the flashing was not seen. Do not accept a glazing-only price that never looks at the flashing, and do not reroof because the unit is misted. The survey has not specified a whole new window and it has not cleared the weathering.
What should you ask your surveyor?
- Has the sealed unit failed, as the misting shows?
- Was the flashing left unseen from outside?
- Have you kept the glass finding separate from the unverified flashing?
What are the typical next steps?
- Treat the misted unit as failed glass.
- Ask a fitter to inspect the flashing from outside when the unit is renewed.
- Do not reroof solely because the sealed unit has misted.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
If the ceiling around the window is dry, is the flashing sound?
Not verified. A dry ceiling does not show the flashing, and the flashing was not seen from outside. The glass has failed, which is a separate fact. Water may not have come through the weathering yet. The survey has not cleared the flashing and has not condemned it. Outside inspection is still the missing look.
Does a misted roof window mean the whole roof covering has failed?
No. The failed part named here is the sealed unit. The roof covering is a different element, and the flashing into it was not even seen. Misted glass is not a decision to strip the slopes. The survey has not said the slates or tiles have failed because the unit has misted.